From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [LML] Vacuum supply for backup gyros
To: lml
Date: Sat, 12 Mar 2005 20:44:39 -0500
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References: <list-790357@logan.com>
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Posted for "Jerry Grimmonpre" <jerry@mc.net>:

  Gary ...
  Obviously you are on to something and the backup vac AI is what I would like
for my glass cockpit.  The vac pump has demonstrated it's unreliability. It
would be nice to have a reliable source of vac to drive only one instrument
... the AI.  Since I am not using a turbo charged engine there is a need for
another vac source that has no periodic cost, no moving parts, reliable and
not sticking out into the wind.
  
  Is there a way to use the 4" venturi to dirve one AI and not have it 
sticking
out into the slipstream as with the early venturis?  The 4" is $50 at Aircraft
Spruce P/N 15050.  Just a thought for those with experience with venturis.
   Can venturis be made to work in an tunnel of high velocity air?
  Regards ...
  Jerry Grimmonpre
  
  

> I'm thinking that at least some turbocharged engine users would like to 
> use
> non-electric (vacuum) gyros as a backup for their fancy glass panels.  I
> have a design (patented, in fact) that allows a turbocharged engine to
> supply the required differential pressure to vacuum instruments under all
> operating conditions without the necessity of a vacuum pump.  This could